Diagnostics/prognostics using wireless links

ABSTRACT

A system and method for monitoring operating parameters of a machine (such as a vehicle) and producing diagnostic and/or prognostic results are disclosed. Active, semi-active, or semi-passive sensors are wirelessly linked with an interrogator that selectively interrogates the sensors, such as through transponders in wired communication with the sensors. A data concentrator or processor analyzes data from certain sensors and generates diagnostic/prognostic conclusions, in some cases using additional data selectively requested from and acquired by the sensors. In some embodiments, raw or abstracted data is communicated with a management center that provides troubleshooting information (again, possibly using additional, selectively acquired data), makes resource management decisions (such as preparing parts or labor resources to make a repair), and tracks problems in all or a subset of the machines being managed.

REFERENCE TO RELATED APPLICATION

Priority is claimed to co-pending U.S. Provisional Patent ApplicationNo. 60/302,244, filed Jun. 29, 2001.

BACKGROUND

The present invention relates to diagnostic/prognostic techniques, andmore particularly, but not exclusively, relates to diagnostic and/orprognostic systems for machines, where the systems include sensors thatcommunicate information through wireless transponders.

As machines become more sophisticated, the desire has grown fortechniques to determine and/or predict machine failures in a morecost-effective manner. The condition-based maintenance approach ofon-board diagnostics and prognostics can substantially reduce thelife-cycle costs of owning and operating machines. However, retrofittingexisting machines with sensors required for on-board diagnostics andprognostics is often impractical due in large measure to the cost andcomplexity of installing the necessary wiring and wiring harnesses.Thus, there is an ongoing need for further contributions in this area oftechnology.

Present diagnostic and prognostic systems and methods suffer fromlimitations in ease, cost, and flexibility of installation. There isthus a need for further contributions and improvements to sensor systemtechnology.

SUMMARY

It is an object of the present invention to provide an improved systemand method for retrieving and processing sensor data regarding theoperation of the machine. This object and others are achieved by variousforms of the present invention.

One embodiment of the present invention is a unique technique forproviding diagnostics and/or prognostics for a machine. Otherembodiments include unique diagnostic/prognostic systems, apparatus, andmethods for machinery.

A further embodiment includes a system for performing diagnostics andprognostics on a machine, especially a mobile or remotely locatedmachine. The system comprises one or more wireless sensors forming anetwork with one or more sensor interrogators, data concentrators,and/or processing nodes, and a way to communicate the resulting datafrom the machine to an operator or an automated monitor. This system isarranged to measure operational parameters of the machine with thesensors, where such parameters might include temperature, pressure,vibration, and/or fluid quality, to name just a few. This informationstream is relayed to the data concentrator, and analyzed by a processingnode to trend certain parameters or sets of parameters. The informationstream and resulting trends are used to make predictions as to remaininguseful life of machine components, fluids, etc. In one form of thisembodiment, the machine is a vehicle.

A still further embodiment includes a diagnostic/prognostic system withone or more sensors, a number of wireless transponders (semi-passive,semi-active, and/or active radio frequency (RF) tags) coupled to thesensors, and one or more data collection devices. The one or more datacollection devices interrogate the transponders to obtain informationabout the operation of the vehicle or other machine instrumented withthe sensors. By virtue of this wireless technology, sensor networks canbe installed on the machine after-market without the need forinstallation of complex and expensive wiring harnesses. As analternative or in addition to such retrofits, the system can beconfigured for new or different applications and upgraded as necessaryby installing the required sensors and their associated transponders.

In another aspect of the invention, an interrogator wirelessly sends aninterrogation signal to a sensor tag. The sensor tag reflects theinterrogation signal using backscatter techniques so that the reflectedsignal indicates a value of an vehicle operating parameter. Theinterrogator communicates the parameter(s) to a processor, whichanalyzes the information to make diagnostic and/or prognosticdeterminations related to the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a vehicle monitoring, management, andmaintenance system that illustrates one embodiment of the presentinvention.

FIG. 2 is a block diagram of communication links between selectedhigh-level components in one embodiment of the present invention.

FIG. 3 is a block diagram illustrating the relationships between certainfunctional components of selected computing resources in the systemillustrated in FIGS. 1-2.

FIG. 4 is a partial cutaway view of selected physical components in avehicular system that is used in one embodiment of the presentinvention.

FIG. 5 is a block diagram of selected functional components in avehicular subsystem that is used in one embodiment of the presentinvention.

FIG. 6 is a schematic view of an interrogator and two forms of sensorunit for use in some embodiments of the present invention.

FIG. 7 is a schematic view of a diagnostic/prognostic network of sensorunits according to one embodiment of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

For the purpose of promoting an understanding of the principles of thepresent invention, reference will now be made to the embodimentsillustrated in the drawings and specific language will be used todescribe the same. It will, nevertheless, be understood that nolimitation of the scope of the invention is thereby intended; anyalterations and further modifications of the described or illustratedembodiments, and any further applications of the principles of theinvention as illustrated therein, are contemplated as would normallyoccur to one skilled in the art to which the invention relates.

Generally, the system and subsystem illustrated in FIGS. 1-6 flexiblyprovide diagnostic and prognostic information based on selected vehicleoperation data, making that information available to relevant personsand computing processes, and analyzing the data to obtain composite,abstracted, and/or synthesized data relating to multiple time periodsand multiple vehicles. Some embodiments can be retrofitted to anexisting vehicle without the expense of installing wiring harnesses tophysically connect each sensor to the data concentration and analysiscomponent(s) of the system. An alternative embodiment, in which sensorunits intercommunicate to acquire and analyze operational data in astationary system, is illustrated in FIG. 7 and will be discussed belowin relation thereto.

The physical connections between components in vehicle management,monitoring, and maintenance system 20 will now be discussed withreference to FIG. 1. An on-board subsystem 30 on some or all vehicles inthe system communicates with other major components of system 20 viamobile network 40 and primary data network 50. Mobile network 40 may be,for example, a cellular telephone system or two-way satellitecommunication system. Data network 50 is preferably (but notnecessarily) a single network, such as the Internet, accessible to eachmajor system component.

Service solution center (SSC) 60 comprises computing units 64 and datarepository 66, which are discussed in more detail below. Also, connectedto this system via data network 50, are one or more fleet operationscenters 70, one or more maintenance centers 80, third-party resources90, and vehicle manufacturer operations center(s) 95.

The paths for the exchange of data between and among the majorcomponents of system 20 will now be discussed in relation to FIG. 2 withcontinuing reference to elements shown in FIG. 1. As can be seen fromFIG. 2, SSC 60 is the communications hub for the components as theyexchange data. As discussed in further detail below, on-boardsub-systems 30 provide selected information concerning the operation ofthe vehicles in the system to SSC 60, which replies with automated andman-in-the-loop responses such as troubleshooting messages and systemstatus updates. SSC 60 also stores and performs analysis of performancedata using data repository 66 and computing unit(s) 64, respectively.SSC 60 provides additional services that will be discussed below inrelation to FIG. 3.

SSC 60 communicates with fleet operations center 70 regarding theperformance and operational status of the vehicles, and with maintenancecenters 80 regarding maintenance issues, such as necessary repairs,maintenance, replacement part availability, and technical manuals, toname just a few. In some embodiments, one or more live technicians(represented in FIG. 2 by dealer support 80) provide some or all of thetroubleshooting responses that SSC 60 sends to on-board systems 30.Manufacturer 95 also receives information compiled at SSC 60 concerningvehicles it made, and can incorporate that real-world data into futuredesigns. When problems are detected in vehicles being monitored by thesystem 20, manufacturer 95 can also provide automated and/orman-in-the-loop troubleshooting assistance. Furthermore, manufacturer 95can use the data acquired through SSC 60 to manage its manufacturing anddistribution of replacement parts.

Third-party resources 90 also obtain information from and provideservices to SSC 60, the vehicles being monitored, and the othercomponents of system 20. For example, third-party resources 90 provideemergency services and navigational assistance to driver/operators basedon the data acquired from on-board subsystems 30.

The interaction among various computing components in on-boardsubsystems 30 and SSC 60 will now be discussed with reference to FIG. 3and continuing reference to FIGS. 1 and 2. In on-board subsystem 30,services 131 are accessible to each primary functional component ofsubsystem 30. Exemplary services 131 include communication services 133,authentication services 135, and advisory, alert, and alarm services137. Communication service 133 transports data between components ofon-board subsystem 30 and other components of system 20. Authenticationservice 135 protects against unauthorized access to subsystem 30 andauthoritatively identifies subsystem 30 when it communicates with othercomponents of system 20. Advisory, alert, and alarm service 137 acceptsrequests by various processes to communicate such items to the vehicleoperator through display 260 (see FIG. 4). A data acquisition (DAQ) andconditioning component 141 acquires data from on-board sensors(discussed in relation to FIGS. 5-6 below). DAQ component 141 filtersand conditions the data stream provided by the sensors in an attempt toremove “bad” data (such as noise and detectable errors) before the datais stored, processed, or communicated through the system. Data bufferingand management component 143 stores the filtered and conditioned dataand provides it to on-board and remote processing components uponrequest.

Diagnostics component 151 analyzes the data to determine whetherproblems or failures have occurred or are occurring in the vehicles'systems, and if so, what these problems or failures are. Prognosticscomponent 153 monitors the data values and trends to predict theremaining useful life of the vehicles' components, fluids, and the like.In performing these functions, diagnostics component 151 and prognosticscomponent 153 can, for example, analyze an incoming data stream from onesensor and, depending on the results, request additional informationfrom another sensor through data buffering and management component 143and DAQ component 141. The results of these analyses are used by othercomponents of system 20 as will be discussed in more detail below.

System status component 155 monitors the values provided by the sensorsand communication links to detect failing and failed sensors and/orfailed communication links. System status component 155 uses rule-basedor neural network-based analysis as would occur to one skilled in theart.

Operational status component 157 synthesizes an overall “health-code”for the vehicle. In the illustrated embodiment, a two-character codeprovides high-level information regarding the functioning of the vehicleto the vehicle's operator via display 260 (see the discussion of FIG. 5below). For example, “OK” indicates that all systems are functioningnormally, while “OC” indicates that the system recommends an oil changeat the earliest opportune time.

SSC 60 comprises services 161, including communication service 163,authentication service 165, process scheduling service 167, andnotification service 169. Communication service 163 manages dataexchange between the objects and components running in SSC 60 and othercomponents of system 20, including on-board subsystems 30.Authentication service 165 protects SSC 60 from improper access usingencryption, passwords, and other methods known to those skilled in theart, as well as authoritatively identifying SSC 60 to the othercomponents of system 20. Process scheduler 167 coordinates andprioritizes activities and/or communications involving SSC 60, whereasnotification service 169 receives, manages, and distributesnotifications among components of system 20 (for example, manufacturers'recall notices from manufacturer operations 95 to on-board subsystems30).

Data collection component 171 handles interactions between SSC 60 andon-board subsystems 30. Data collection component 171 feeds that datathrough access control component 173 to data/information managementcomponent 175, which stores the relevant data in data repository 66 (seeFIG. 1). Prognostics component 181 analyzes the data stored indata/information management component 175, adding its data and computingresources to the activities described for prognostics component 153 ofon-board subsystems 30. When additional information is desired for aprognosis and/or diagnosis analysis or decision by prognostics component181, the information is requested in a request message from SSC 60 tothe particular on-board subsystem 30. The requested information is thenacquired by DAQ component 141 and communicated back to prognosticscomponent 181 as discussed above in relation to the primary data stream.

Software agent management component 183 generates, monitors, maintains,and manages software agents as discussed in further detail below.Analysis component 185 provides high-level analyses of data stored indata/information management component 175, as well as data miningfunctions as would occur to one skilled in the art. Reporting component187 provides a variety of views of the collected data for reporting tovarious persons, computers and/or entities as would occur to one skilledin the art.

An on-board subsystem 220 of one embodiment of the present inventionwill now be discussed in relation to FIG. 4, and may correspond in someembodiments of the invention to an on-board subsystem 30 in FIGS. 1-3,to which continuing reference will be made. Sub-system 220 includes aground transport vehicle 222 with engine compartment 224 and vehicleoperator compartment 226. A cutaway of engine compartment 224 reveals aschematically depicted control system 230 and internal combustion engine240. Control system 230 monitors and regulates operation of engine 240,which is the primary source of motive power for vehicle 222. In vehicleoperator compartment 226, a display 260 visible by an operator inoperator compartment 226 is also illustrated, as will be more fullydescribed hereinafter. Telematics control unit (TCU) 250 communicateswith control system 230 and incorporates transceiver functionality forcommunication between control system 230 and SSC 60.

Selected components of subsystem 220 will now be discussed in relationto FIG. 5, with continuing reference to FIGS. 1-4. Sensor units 232 a,232 b, 232 c, and 232 d (generically and collectively referred to assensor unit(s) 232) each detect one or more operating parameters ofvehicle 222 and convert those parameters to digital values. Interrogator234 (consisting, for example, of a 430 processor from Texas Instrumentsof Dallas, Tex., U.S.A., and one or more DSP ICs from Analog Devices,Inc. of Norwood, Mass., U.S.A.) occasionally and selectivelyinterrogates certain individual sensor units 232, which respond bywirelessly transmitting back to interrogator 234 a reply signal toindicate the value(s) of the requested sensed quantities that it mostrecently detected. This communication is preferably conducted using apublished protocol, such as the MIT Auto ID Protocol.

Interrogator 234 converts the reply signal from the respective sensor232 into a digital signal, and forwards that digital signal to dataconcentrator 236. Concentrator 236 may, for example, be a Redi-ProController from Pacific Northwest National Laboratory of Richland,Wash., U.S.A. Data concentrator 236 monitors the data values returnedfrom sensors 232 and performs analysis on them, such as the computingservices and components shown in FIG. 3. As discussed below, certainresults of that analysis and outputs of those components arecommunicated to the operator of the vehicle via display 260, while otherresults are communicated to SSC 60.

The embodiment illustrated in FIG. 5 shows some examples of sensors andoperating parameters that might be used in some embodiments of thepresent invention. Sensor 232 a measures the temperature of coolant inengine 240, while sensor 232 b measures oil pressure and quality. Sensor232 c detects and quantifies vibration in the vehicle's transmission,while sensor 232 d measures tire pressure. Data concentrator 236monitors these operational parameters to detect any variation outside aproper range of values. For example, the tire pressure detected bysensor 232 d might properly be 18 PSI, but it may be that little damageis caused or safety risk incurred if the pressure is between about 16and 20 PSI. Data concentrator 236 checks the detected values againstthis range of acceptable values and reports deviations therefrom to theoperator of the vehicle via display 260 and to the SSC 60 via TCU 250.Data concentrator 236 also checks the detected parameters for rates ofchange that exceed acceptable levels. This latter technique can providean earlier warning of a failure. For example, a parameter normallybetween 75 and 1000 might have several samples near 150 followed by asample at 700 units. Although the sample is still within the acceptablerange, the rapid change could indicate a catastrophic failure that,using the present system, can be immediately detected, investigated, andreported.

The values and changes in the values over time are also used by dataconcentrator 236 to predict failures and more accurately estimate theuseful life of various components or the need for service or maintenancework. For example, early replacement of a vehicle's tires might beindicated following an extended period of operation at tire pressuresoutside the tires' specifications. That indication is communicated tothe operator via display 260 with a message such as “TIRE REPLACEMENTINDICATED IN 2000 MILES” or by a two-character code (“T2”, for example)as described above in relation to FIG. 3. A similar message is generatedat SSC 60, where automated equipment places an order for the new tiresto be delivered at or near the expected location of vehicle 22 after ittravels about 2000 more miles. Display 260 might or might not indicatewhether that information has been transmitted to SSC 60.

The general structure of sensor units 232 will now be discussed inrelation to FIG. 6 with reference to certain components shown in FIGS. 4and 5. Vehicle 222 is instrumented with one or more sensor units 232that are each communicatively linked to interrogator 234 by a wirelesstransponder 272. The wireless transponder 272 is in the form of an RFtag arrangement 274. In some embodiments, the RF tag 274 and sensorunit(s) 276 is/are provided as a unit with which one can retrofitvehicle 222. In an alternative embodiment, shown as sensor unit 232 f,one RF tag 274 can manage data from multiple sensors 276 usingtechniques that would occur to one skilled in the art. In suchembodiments, RF signals 270 can be modulated to elicit responses from aselected one or more sensors 276.

Interrogator 234 uses radio frequency interrogation signals 270 toselectively stimulate one or more RF tags 274 to receive informationsensed with the corresponding sensor(s) 276 in response. In variousembodiments, sensor(s) 276 may be one or more of an XTM-190 seriesminiature pressure transducer (available from Kulite SemiconductorProducts, Inc., Leona, N.J., U.S.A.), custom-manufactured thermocouples(such as those sold by NANMAC of Framingham, Mass., U.S.A.), a BelhavenARIS 1-8 channel infrared analyzer (supplied by Belhaven AppliedTechnologies of Kennewick, Wash., U.S.A.), miniature piston viscometer(such as model 570 or 372J from Cambridge Applied Systems of Medford,Mass., U.S.A.), or elemental analysis components (such ascustom-designed components or models CT 5000 or CT 8000 from KeyMasterTechnologies of Kennewick, Wash., U.S.A.).

An alternative embodiment of the present invention will now be discussedwith reference to FIG. 7. Generally, FIG. 7 shows a system 300comprising an oil well 310 that sends oil to station 320 throughpipeline 330. Pumping substations 331-336 pump the fluid from well 310to station 320 as is known in the art of oil transport. At each pumpingstation 331-336 is installed a sensor unit 341-346, respectively. Inaddition, sensor unit 347 is installed in the pipeline segment betweenpumping stations 335 and 336. Sensor unit 340 detects operatingparameters of well 310.

The configuration illustrated in FIG. 7 has several properties that areadvantageous to many different uses of the invention. For example,certain of sensors 340-347 communicate with each other. Data from sensorunit 342 can be communicated through sensor unit 341 and antenna 325 todata storage and analysis resources at station 320. In fact, the sensorunits 341-344 at pumping stations 331-334, respectively, can communicatenot only with base station antenna 325 and sensor units on adjacentpumping stations, but also with sensor units on pumping stations thatare two segments away (e.g., the sensor unit 344 at pumping station 334can communicate directly with sensor unit 342 at pumping station 332,which can communicate directly with antenna 325). In this manner, evenif a single sensor unit fails, information can still be shared betweenthe main station 320 and sensor units further down the line from thefailed sensor unit, without the base station 320 having to communicatedirectly with each sensor unit. Likewise, requests for additional datacan still travel from station 320 to sensors upstream of the failedunit.

Sensor units 345, 346, and 347 communicate their data to station 320 viasensor unit 340 and transceiver/antenna 315. In this embodiment, sensorunit 340 comprises logic that analyzes data from sensor units 345-347 togenerate status information and/or higher-level data for communicationto station 320. In some embodiments, sensor unit 340 further compriseslogic to generate alerts based on the sensed data, as was discussedabove in relation to diagnostics and prognostics components 151, 153,and 181 in FIG. 3. Transceiver/antenna 315 communicates the sensedand/or abstracted data through public switched telephone network (PSTN)350 with station 320 constantly, periodically, and/or upon generation ofan alarm event by the sensor network as discussed above in relation toFIGS. 3-5. The communications link between transceiver/antenna 315 andPSTN 350 may be of the conventional digital or analog variety. In somevariations of this embodiment, the connection betweentransceiver/antenna 315 and station 320 is a direct data link of eithera wired or wireless variety.

Encryption and authentication techniques are applied to the dataexchanged among components of system 20 or system 300, as mentionedabove in relation to components 135 and 165 in FIG. 3. These techniquesmight, for example, use public-key cryptography, shared-key (or “privatekey”) cryptography, Diffie-Hillman key agreement techniques, messageauthentication codes (MACs), message digests, and other techniques aswould occur to one skilled in the art.

It is noted that, as used herein, “machine” may be broadly interpretedto encompass any wholly or partially mechanical system that has orinteracts with an environment having a measurable quantity that reflectsa system status or performance. Of many possibilities, some examplesinclude vehicles, stationary manufacturing equipment, computers, andbuildings. In addition, a “subsystem” is a system designed, arranged, oradapted to be used in, or integrated with other components to make upanother system.

Furthermore, it will be seen by those skilled in the art that a varietyof types of data may be communicated between components of this system.For example, in system 20 shown in FIGS. 1-6, a sensor 232 might providespectrum analysis data to data concentrator 236, which could detectwater in the engine's oil system based on that data. Data concentrator236 might then communicate a “water in the oil” signal via TCU 250 toSSC 60. A person or computing process at SSC 60 could then send aresponse message back, comprising a request for temperature and vehiclespeed data. Data concentrator 236 then uses interrogator 234 to acquirethe requested data, then communicates that data back to SSC 60 in one ormore reply messages. Depending on the information in the replymessage(s), SSC 60 can issue advice to the operator of vehicle 222regarding operation of that vehicle until repairs are made, can preparefor staffing needs at a maintenance center 80, and can adjust fleetscheduling through a fleet operations center 70. The ability provided bythe present invention to interactively and selectively inquire ofvarious sensors would, at least in this case, reduce the amount ofinformation that had to be continuously exchanged between vehicle 222and SSC 60 in order to make informed diagnosis/prognosis decisions, toenable integration with many outside systems, and to allow a much morecomplete diagnosis without requiring wired connections between thesensors, analysis hardware, and telematics hardware. Many additionaladvantages will be apparent to those skilled in the art.

Sensor units 232 and their components may be powered in severaldifferent ways, depending on the particular sensor configuration, thelocation of sensors in the vehicle, cost constraints, and other designcriteria, as would occur to one skilled in the art. For example, RF tags274 may be powered by vehicle power, a battery connected to the tag, orthe interrogation signal itself, to name just a few options. It is notedthat, although the above description uses terminology characteristic ofcommunications using active or semi-active tags, the invention may alsobe implemented without undue experimentation in systems that usesemi-passive RF tags in systems that use semi-passive RF tags. Some suchimplementations have the advantage over active-tag embodiments of lowerpower requirements and complexity at the sensor site, which enablessensors to be placed in locations not typically serviceable by activetags.

All prior applications and other documents cited herein are herebyincorporated by reference in their entirety as if each had beenindividually incorporated by reference and fully set forth.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly selected embodiments have been shown and described and that allchanges and modifications that would occur to one skilled in therelevant art are desired to be protected.

What is claimed is:
 1. A system, comprising: a processor; a wirelesssignal transceiver in communication with said processor; two or moresensors configured to detect two or more operating parameters of amachine and generate corresponding parameter information signals; one ormore transponder means configured to receive the parameter informationsignals from said sensors and wirelessly communicate the operatingparameter data to said wireless signal transceiver in response to aselective interrogation signal; a processor-readable medium, incommunication with said processor, encoded with programming instructionsexecutable by said processor to: control generation by said transceiverof the selective interrogation signal, and perform computations on theoperating parameter data.
 2. The system of claim 1, wherein saidcomputations comprise determining a machine state as a function of theoperating parameter data.
 3. The system of claim 2, further comprising adisplay means, in communication with said processor, for visuallycommunicating the machine state to a person.
 4. The system of claim 3,wherein: the machine has an operator compartment; and said display meansis in the operator compartment.
 5. The system of claim 2, furthercomprising: a stationary monitoring facility in communication with saidprocessor through a wireless link; and a state message from saidprocessor to said monitoring facility through said wireless linkreflecting the machine state.
 6. The system of claim 5, wherein thecommunication between said monitoring facility and said processor passesthrough a public access data network.
 7. The system of claim 5, whereinsaid wireless link comprises a public access cellular communicationsnetwork.
 8. The system of claim 5, wherein said wireless link is atwo-way link.
 9. The system of claim 8, further comprising a responsivemessage from said monitoring facility to said processor, where theresponsive message is sent in response to state messages that indicateone or more predetermined machine states.
 10. The system of claim 9,wherein said responsive message is a request for specific additionaldata regarding one or more of the operating parameters; and furthercomprising a reply message through the wireless channel from saidprocessor to said monitoring facility containing the requestedadditional data.
 11. The system of claim 1, wherein at least onetransponder means is an RF tag.
 12. The system of claim 11, wherein theat least one transponder means includes no internal power source. 13.The system of claim 11, wherein the at least one transponder meanscomprises an internal power source.
 14. The system of claim 11, whereinthe at least one transponder means shares a power source with themachine.
 15. The system of claim 1, wherein at least a first one of saidone or more transponder means is further configured to: generate aselective interrogation signal to which a second one of said one or moretransponder means is configured to respond; receive the parameterinformation signals from the second transponder means; and communicatethe parameter information signals to said wireless signal transceiver.16. A system, comprising: a processor; a wireless signal transceiver incommunication with said processor; one or more sensors collectivelyconfigured to detect two or more operating parameters of a vehicle; oneor more tag means for receiving the operating parameters from saidsensors and wirelessly communicating the operating parameters to saidwireless signal receiver; a processor-readable medium, in communicationwith said processor, encoded with programming instructions executable bysaid processor to: develop a report signal as a function of theoperating parameters; and send said report signal to a display device.17. The system of claim 16, wherein: the vehicle has an operator'scompartment; and the display device is configured to be observed by aperson in said operator's compartment.
 18. The system of claim 16:further comprising a fleet command center; and wherein the displaydevice is configured to be observed by a fleet operator in said fleetcommand center.
 19. The system of claim 16, wherein said report signalreflects the result of processing a plurality of the operatingparameters.
 20. The system of claim 19 wherein said report signalreflects diagnosis based on a plurality of operating parameters.
 21. Thesystem of claim 19, wherein said report signal reflects a prognosisbased on a plurality of operating parameters.
 22. The system of claim16, wherein at least one of said one or more tag means is an RE tag. 23.The system of claim 22, wherein said RE tag is semi-passive.
 24. Thesystem of claim 22, wherein said RE tag is semi-active.
 25. The systemof claim 22, wherein said RE tag is active.
 26. The system of claim 16,wherein said programming instructions are executable by said processorto: effect an interrogation of said one or more tag means to obtain oneor more data signals; and perform at least one computation on said oneor more data signals.
 27. A system for maintaining a plurality ofvehicles, comprising: a management center; and an on-board subsystem oneach vehicle, each said subsystem comprising: one or more sensors thatcollectively sense a plurality of operating parameters of the vehicle;one or more transceivers, each in communication with one or moresensors, that communicate a data signal indicative of the operatingparameters in response to an interrogation signal; one or moreinterrogators configured to selectively produce the interrogationsignals and receive the data signals; a processor, in communication withsaid one or more interrogators and a computer-readable medium, whereinthe computer-readable medium is encoded with programming instructionsexecutable by said processor to: perform analysis of the health of oneor more portions of the vehicle based on the operating parametersindicated by the data signals to produce one or more result signals; andcontrol production of interrogation signals by said one or moreinterrogators; and communications hardware in communication with saidprocessor to communicate at least one of said one or more result signalsto said management center.
 28. The system of claim 27, wherein saidmanagement center is configured to generate a response signal to saidone or more result signals and send it to said communications hardware.29. The system of claim 28, wherein said response signal indicatesinstructions to an operator of the vehicle.
 30. The system of claim 28,wherein: said response signal comprises a request for additionalinformation concerning additional operating parameters of the vehicle,where the additional operating parameters were not described in saidresult signal; and the programming instructions are further executableby said processor to: cause said one or more interrogators toselectively request the additional information; cause saidcommunications hardware to transmit the additional information to saidmanagement center.